Question:How were the models of Copernicus and Ptolomy different from each other and from the modern day model?
Both the models where wrong because they both put either the Sun or the Earth at the centre of the Universe.
We now know that the Solar System is nowhere near the centre of the universe.
Copernicus' Heliocentric model did greatly improve upon Ptolomy's Geocentric model by replacing the Earth with the Sun as being at the centre of the Solar System, which is the correct position.
However the Copernican model used circular orbits, which we now know should have been elliptical, and caused inaccuracies in predictions of the motion of the planets.